1. Technical Field of the Invention
The invention relates generally to safety devices in a combustible environment and more particularly to static discharge reduction between a nozzle and a static-electrical charged object.
2. Description of Related Art
Fuel dispensing nozzles are well-known in the art for dispensing fuel from a fuel supply into a container. A typical example would be the fuel dispensing nozzle at a retail gasoline station wherein the dispensing nozzle is at the end of a hose connected to a dispenser which is connected to an underground storage tank. The nozzle will typically contain a valve that is actuated by the customer to dispense fuel from the underground storage tank through the dispenser, through the hose, through the nozzle and into the customer's vehicle or gasoline can.
It is understood in the industry that dispensing volatile fuel may present a fire hazard if an ignition source is present near the dispensing nozzle. The danger is created by the fuel vapor emanating from the nozzle container interface. Therefore, it is common for fuel stations to have signs which require users to turn off their vehicles and not light cigarettes in the area of fuel dispensing to prevent such fires. Unfortunately, customers are injured from fires started by static discharge in the area immediately surrounding the nozzle.
While each case is different, two patterns have developed where static discharge is a factor. One pattern involves fuel dispensed into a gasoline can and not the fuel tank of a vehicle. In this scenario, the can is placed on a surface that is electrically insulative, as opposed to conductive, and as the fuel is discharged from the nozzle into the can, static electricity builds up in the can. Then, as the nozzle is withdrawn from the can, the metallic highly electrically conductive nozzle spout may pass in close enough proximity to a statically-charged portion of the can to cause a static discharge between the can and the spout, which under the right conditions, can ignite the vapor in the immediate area causing a fire which can damage property and cause personal injury.
A second scenario which has proven to cause fires in the gasoline dispensing station involves a customer locking the nozzle open while fuel is being dispensed into the vehicle fuel tank and either returning to their seat in the vehicle or going into the convenience store. The act of sliding in and out of a vehicle, or walking across a carpeted floor, can cause static electricity to build up in the customer's body. After a static charge has built up within the customer's body, a static discharge can occur between the customer and the nozzle body or other portion of the nozzle when the customer reaches down to grasp the nozzle. In such a situation, flammable vapor or fumes may have built up in the area of the nozzle such that a fire or explosion may be ignited that is capable of causing damage to property and personal injury.
Attempts to prevent sparks in this environment include the addition of grounding straps to fuel tank filler pipes and other surfaces to prevent the build up of static electricity while filling the vehicle. Unfortunately, these grounding straps do not address the build-up of static electricity in the customer's body as they are moving across the seat of their vehicle or walking on the carpet in the convenience store, nor do they address the build-up of static discharge in a gasoline can that is placed on an insulative surface, such as a bed liner of a pickup truck. In order to address these risks, it has been known to instruct users to place gasoline cans on the ground and have users touch conductive surfaces distant from the nozzle prior to touching the nozzle end to discharge any static electricity in the customer's body.
To the extent users do not follow the directions clearly labeled on the dispenser, the above methods do not effectively reduce the static discharge occurrence in and around the nozzle area. A system is required that would effectively eliminate static discharge in and around the nozzle area without requiring specific actions by the customer.